"We now have quite clearly loyalist paramilitary organisations who have now directed gunfire at police officers, who are out there trying to uphold the law and prevent anarchy on our streets," he said.

"It is a serious situation, it's one of the most difficult situations that the police service of Northern Ireland have faced in the last 10 years."

Protests began a month ago after a vote by councillors to end the century-old tradition of flying the British flag from Belfast City Hall every day.

Thirteen people were charged with public order offences on Saturday, one of them in relation to that day's rioting, and the other 12 from disorder on Friday night, during which nine police officers were injured.